1. Field of the Invention
The present invention relates to a roving bobbin exchanging method for a spinning frame and an apparatus for carrying out the roving bobbin exchanging method. More particularly, the present invention relates to a roving bobbin exchanging method for exchanging a pair of almost exhausted roving bobbins suspended by the front and back bobbin hangers of a creel of a conventional ring spinning frame for a pair of full packaged roving bobbins suspended by the bobbin hangers of a supply rail extended in front and above the creel of this spinning frame.
2. Description of the Related Art
When roving bobbins suspended by the bobbin hangers of a spinning frame become almost exhausted, they must be exchanged for full packaged bobbins.
Automation of the roving bobbin exchanging operation for spinning machines has been eagerly sought to reduce the manpower needed in the spinning process. For example, Japanese Unexamined Patent Publication (Kokai) No. 61-102428 discloses a roving bobbin exchanging method applied to a conventional ring spinning frame wherein, at each side of the frame, front and back rows of bobbin hangers of a creel are arranged along the longitudinal direction of the frame to supply rovings to the corresponding draft parts of the corresponding side of the frame. Two rows of supply rails are arranged along each creel of this spinning frame. A pair of front and back roving bobbins suspended by the corresponding bobbin hangers, one of which is supported by the front row and the other by the back row, are exchanged for full packaged roving bobbins suspended by the corresponding bobbin hangers of the supply rails, one of which is supported by the front supply rail and the other by the back supply rail. The above-mentioned bobbin exchanging operation is carried out sequentially from one end to the other of this spinning frame.
Japanese Unexamined Patent Publication (Kokai) No. 61-119728 discloses another roving bobbin exchanging method applied to a conventional ring spinning frame which utilizes a single supply rail. In this invention, alternate pairs of roving bobbins arranged in front and back rows, respectively, at regular bobbin pitches along the longitudinal direction of the spinning frame are exchanged for corresponding adjacent two full packaged roving bobbins suspended by the bobbin hangers of the single supply rail when the alternate pairs become almost exhausted.
The methods disclosed in the above-mentioned two Japanese unexamined patent publications employ two pairs of pegs, namely, a pair of pegs for displacing a pair of almost exhausted roving bobbins and a pair of pegs for displacing a pair of full packaged roving bobbins, to carry out the roving bobbin exchanging operation.
If an automatic piecing operation of rovings is required in combination with the above-mentioned roving bobbin exchanging operation, if the free end of the roving of each full packaged roving bobbin suspended by a bobbin hanger of the supply rail is first caught and then introduced to a running roving from an almost exhausted roving bobbin suspended by a corresponding bobbin hanger of the creel and pieced with the above-mentioned running roving at a position upstream of the corresponding draft part, the operation for exchanging the almost exhausted roving bobbin for the full packaged roving bobbin is then carried out. Thereafter, the roving bobbin exchanging operation is carried out for other pairs of almost exhausted roving bobbins suspended by a front bobbin hanger or a back bobbin hanger, facing each other, of a spinning frame, as a unit operation and the unit operation is successively carried out along the creel from one end to the other of the spinning frame.
Because the above-mentioned two pairs of pegs are provided with different working functions, the utilization of such two pairs of pegs causes the creation of a complicated construction of the roving bobbin exchanging apparatus. Moreover, if it is desired to carry out a combined operation of the above-mentioned roving bobbin exchanging operation with an automatic roving piecing operation, the construction of the apparatus for carrying out such a combined operation becomes more complicated so that the practice of such a combined operation becomes impossible.